Clinicopathologic study on clear cell hepatocellular carcinoma.

In order to study the clinicopathologic characteristics of the clear cell variant of hepatocellular carcinoma (HCC), 215 consecutive cases measuring less than 5 cm in diameter were reviewed. The cases were divided into clear cell HCC (20 cases); focal clear cell HCC (77 cases); and non-clear cell HCC (118 cases). Clinical and pathological findings were compared among these groups. Clear cell HCC was moderately differentiated in 80% of cases and the incidence was not related to tumor size. The male to female ratio was 2.3:1, lower than the 6.9:1 of non-clear cell HCC. The association rate with liver cirrhosis was 90%, higher than the 59.3% of non-clear cell HCC. Three- and five-year survival rates, and no recurrence time were 54.5%, 33.3%, and 564 days, respectively, lower than the findings of 74.3%, 46.1%, and 770 days for non-clear cell HCC. But there is no significant difference in prognosis between both groups. Ultrastructurally, clear cells showed abundant glycogen storage and a variable degree of fat vacuoles, with a marked reduction of the number and size of organelles in the 8 cases examined. Non-clear cells of focal clear cell and non-clear cell HCC showed a moderate degree of glycogen storage in 85.7% and 28.6% of the seven cases examined from each group, with significant difference. It was concluded that clear cell HCC occurs mostly in the moderately differentiated form and is characterized by high female prevalence, high rate of association with liver cirrhosis, and has no significant difference in prognosis compared with non-clear cell HCC.